Time-variant serviceability reliability analysis of anchored rock slopes deformation

A non-intrusive stochastic finite element method for time-variant serviceability reliability analysis of anchored rock slopes with consideration of rock bolt corrosion is proposed. A rock bolt corrosion model reflecting the variation of the anchored force of each rock bolt with service time is established. Consequently, the computational procedure for time-variant serviceability reliability analysis of the slope deformation using the non-intrusive stochastic finite element method is proposed. The relationship between the probability of failure for slope deformation and the maximum allowable deformation is investigated; and a method for determining the maximum allowable deformation of the slope is proposed based on parametric sensitivity analysis. An example of reliability analysis of anchored rock slope deformation subjected to surcharge loading is illustrated to demonstrate the validity and capability of the proposed method. The results indicate that the proposed non-intrusive stochastic finite element method can effectively evaluate time-variant serviceability reliability of rock slopes. The rock bolt corrosion has a significant influence on the serviceability reliability of rock slopes as the service time of rock bolts increases. In addition, an approximate linear relationship exists between the logarithm of the time-variant probability of failure for slope deformation, lgpf, and the maximum allowable deformation; and this linear relationship becomes more obvious as the reliability level of the slope increases

Effects of the constitution of CrON diffusion barrier on the oxidation resistance and interfacial fracture of duplex coating system

The duplex coating system of a NiCrAlY overlayer with a CrON diffusion barrier with different phase contents was deposited by AIP method. The duplex coatings were characterized regarding their microstructure, and the ability of the diffusion barrier was evaluated. The oxidation resistance and the interfacial strength of the duplex coatings were investigated. The results indicated that the duplex coating system with a diffusion barrier with an O/N ratio ∼66 and a lower Cr2O3 phase content exhibited more excellent oxidation resistance and lesser interdiffusion than with a diffusion barrier with O/N ∼30.1. The exposed coating samples possessed an improved interfacial strength compared with the annealed samples in the two duplex coating systems. The stronger interfacial strength in the coating system with a diffusion barrier with a low Cr2O3 phase content was related to the fewer defects and lower residual stress in the diffusion barrier